Appliance for radiographic representation of sections of the body



April 1957 JOHANN (HANS) DUMER 2,789,231

APPLIANCE FOR RADIOGRAPHIC REPRESENTATION OF SECTIONS OF THE BODY Filed June 9, 1953 2 Sheets-Sheet 1 Fig.2

IN V EN TOR.

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United States Patent APPLIANCE FOR RADIOGRAPHIC REPRESENTA- TION OF SECTIONS OF THE BODY Johann (Hans) Dumer, Linz (Danube), Austria Application June 9, 1953, Serial No. 360,413 Claims priority, application Austria November 26, 1952 2 Claims. (Cl. 25061.5)

Appliances for transverse tomography of the human body are already known in which an object support and a film support are used which are both rotated at the same speed. The coupling of the movements has in this case been produced hitherto by mechanical means. However, since the film support has to be capable of easy adjustment horizontally, vertically and angularly, there have been produced constructions which are not only complicated and expensive, but in which also defects in the synchronism of the object support and film support were produced, these defects being caused by the inertia of the flexible shaft and friction losses.

The subject of the invention is an appliance for radiographic representation of sections of the body, in which these disadvantages are obviated by the fact that for the purpose of transmitting the rotational movement between the object support and the film support, there is provided a rotating field system by which an accurate synchronous running is produced.

Although in all hitherto known appliances, it has theoretically been assumed possible accurately to adjust the tube and the axes of the object support and film support, it has nevertheless been found as a result of experiments that this cannot be carried out in practice. It was only possible to obtain a substantially correct axis setting by tedious adjustments. The reason for this is that there does not exist any normal X-ray tube arranged on a normal stand which permits of such adjustment without supplementary expedients. However, since a particularly accurate adjustment between the X-ray tube, the axis of the object support and the axis of the film support is absolutely necessary for the production of satisfactory exposures, it must be possible to carry out a correction of setting.

According to the invention, this is achieved by the fact that the film support axis is adjustable perpendicularly of the central beam of the X-ray tube. Instead of this arrangement, it is also possible for the object support to be adjustable perpendicularly of the central beam of the X-ray, or the entire appliance or the base thereof can be rocked about an axis parallel to the axis of the object support or of the film support.

By way of example, one embodiment of the subject of the invention is used for illustration purposes in the accompanying drawing, wherein,

Figure 1 is an elevation of the complete appliance.

Figure 2 is a plan view thereof.

Figure 3 shows diagrammatically the means for transmitting movement.

Figure 4 is a plan view corresponding to Figure 3.

Figures 5, 6 and 7 show diagrammatically, the mutual arrangement of the X-ray tube, the object support and the film support.

Rotatably arranged on the base 1 of the appliance are rollers 2 which support the disc 3 near its periphery and thus provide a steady mounting thereof. Rigidly connected with the disc 3 is a pillar 4 which comprises at its upper end a guideway for a slide 6 which is adapted to be screwed on a spindle 7. The latter is mounted in the guideway 5 and can be turned by means of hand-wheel 8.

The slide 6 carries the saddle 9 and also the back-rest 10 shown in section in Figure l.

The parts 3 to 10 form the object support, which are fitted on a driver shaft 11 which is mounted in the base 1. The latter carries a gear wheel 12 (Figure 3), which is driven by an electric motor 14 by way of the pinion 13. Meshing with the gear wheel 12 with a. step-up ratio is a pinion 15 which drives a rotating field system 16 (synchrotransmitter). This rotating field system is connected by a quintuple (five-pole) flexible cable 17 with a second rotating field system 18 (synchro-receiver). Two of the five poles of the rotating field systems 16 and 18 (i. e. the two poles of the stators, when the rotors have three phases or the two poles of the rotors, when the stators have three phases) are connected to the alternating current network. The both rotating field systems form a so-called electric shaft.

By means of a pinion 19, the rotating field system 18 drives the gear wheel 20 which is connected with the film cassette holder 21. The parts 18 to 21 are arranged or mounted in the slide 22 (Figure l) and form therewith the film holder.

The slide 22 is guided on two slide bars 23 (Figure 2), which are rigidly connected with the two supports 24. The slide 22 is in the case adapted to be screwed on a spindle 25 which can be turned by means of a setting knob 26.

The supports 24 are rigidly arranged on a base plate 27 which is connected to two guide rods 28. The latter pass through horizontal sleeves 29, which are connected with a vertical sleeve 30. The latter slides on a vertical guide tube 31 and depends from a chain 32 which is guided over a chain wheel 33 and on which is suspended a counter-weight 34 inside the guide tube 31. The guide tube is detachably connected with base 1. For the purpose of fixing the rods 28 in the sleeves 29 or in the sleeve 30 on the guide tube 31, there are provided screws which are provided with turning heads 35 and 36, respectively.

As shown in Figure 5 in conjunction with Figure 1, when the setting is correct, the central beam drawn 38 from the focal point of the X-ray tube 37 intersects the object axis (axis of the object carrier) 39 and the film sup port axis 40, intersecting the latter at the centre point of the film cassette holder 21.

Figure 6 illustrates an incorrect setting. The central beam 38 in this case intersects the axis 39 of the object support, which can always be arranged, but the axis 40 of the film support is outside the central beam. A deyiation of the tube setting, which must be exactly degrees with respect to the axis of the central beam, by only one degree, that is to say, to 89 or 91 degrees, already produces an incorrect setting with which it is no longer possible to make a serviceable exposure.

As will be seen from Figure 7, the correction of the incorrect adjustment shown in Figure 6 is effected by displacing the film support axis 40 laterally, which is achieved by turning the setting knob 26.

The adjustment of the film support in the vertical direc tion and in the direction towards the object support can be effected by displacing the sleeve 30 on the guide tube 31 or the rods 28 in the sleeves 29.

If a tomographic X-ray exposure is to be made, the person to be examined takes up a position on the saddle 9, supporting himself against the back-rest 10 and placing his feet on the plate 3. By operating the hand-wheel 8, the part of the body which is important for the examination can be brought closer to the object support axis 39. A film is now placed in the cassette holder 21 and the motor 14 is set in operation. The object support is rosections by an X-ray tube comprising an object support and film support, each rotatable about its axis, operable means for horizontally adjusting, the vertical axis of the film support relative to its intersection with the central beam of the X-ray tul'ae, a motor rotating the object support, a first rotating electric field system rotated by the object support, a second rotating electric field system driven by the first system and rotating the'filrn support. 2. The apparatus according to claim 1 and wherein the operable adjusting means is a screw spindle.

References Cited in the file of this patent UNlTED STATES PATENTS 2,196,618 Watson Apr. 9, 1940 2,281,931 Frank May 5, 1942 2,300,334 Bergman s ha Oct. 27, 1942 

